* Prior to the "birther bill," the state was the first to pass an ultra-restrictive immigration law requiring law enforcement to check the legal status of people they detain. Part of the bill was struck down by the Supreme Court, but other states passed similar bills after Arizona.

* A 2012 Arizona abortion law that was considered one of the toughest in the country was struck down by the courts. The bill, like similar laws in other states, banned abortions after 20 weeks of pregnancy, but its definition of pregnancy began two weeks earlier than other bans, making it effectively an 18-week ban.

So, the question is, why? Why Arizona? Why, when 21 states were redder in the 2012 election, is Arizona outpacing all of them when it comes to pushing conservative -- and often controversial -- legislation?

We talked to some smart Arizona folks, and we got several plausible theories. Below, we take a look at a few of them.

1) Public financing of campaigns

This was, by far, the most oft-cited reason.

Arizona is one of the few states -- and the only GOP-controlled red state -- that offers to fully fund the campaigns of candidates for state and legislative offices. What does that mean? It means the playing field has been leveled for pretty much anybody who wants to run.

All a state legislative candidate needs to do to earn public financing is to get a $5 contribution from less than 300 people. From there, they get $15,000 for the primary and $22,000 for the general election. That's real money in a state legislative race -- especially since candidates who opt out of the public financing program have their contributions capped at less than $500.

(Worth noting: In recent years, the state's public financing system has begun to unravel. The contribution limit was recently increased to $2,500 -- similar to the federal limits -- making the public financing system less appealing and less relevant going forward. And the Supreme Court in 2011 struck down another portion of the law that helped publicly financed candidates get more money when outside groups target them.)

Arizona political watchers say this system has lowered the bar when it comes to who is viable and allowed ultra-conservative candidates to get the money they need to win primaries.

"Look at [the] legislature, and most conservative voices are all people who were elected because they get the check from the taxpayers to run their campaign and don’t have to get money from anyone, including the business community," said one Arizona Republican, granted anonymity to discuss the matter candidly.

2) Term limits

Arizona also limits its state representatives and state senators to eight years in each chamber, leading to significant turnover and to relatively inexperienced politicians calling the shots. (This is also the case in 14 other states, of course.)

3) Lack of community

Arizona is full of transplants and retirees, and its population is very spread out. One Arizona Republican said this leads to less sense of community and more campaigning through the media and yard signs. It also means retirees -- who tend to be more socially conservative and more politically active -- drive the debate in GOP primaries.

4) There's just something about Arizona

All of the above doesn't account for one key fact: This isn't really all that new for Arizona.

This is, after all, the state of Barry Goldwater, who led the conservative movement in the 1960s and really redefined what it meant to be conservative.

It was also the last state to adopt a Medicaid program and the second-to-last state to adopt Martin Luther King Day as a holiday.

A Democratic governor declared the MLK holiday in 1986, only to have his GOP successor rescind that decision. The issue went on the ballot in 1990, with 76 percent voting against the holiday. The vote cost the state the 1993 Super Bowl -- just as some worry the current bill could cost the state the 2015 Super Bowl. The state voted again in 1992 and approved the holiday.

The controversy was even the subject of a Public Enemy song:

In other words, Arizona has a long history of this kind of thing. Public financing, term limits and other factors might play into what's happening in Arizona, but the state is no stranger to staking out unique and very conservative positions.

Is there anything we missed? Take to the comments section below to let us know your theories.

Update 5:25 p.m.: Grady Gammage Jr., senior fellow at the Morrison Institute at Arizona State University. asked the same question we asked in our headline during a speech a few years ago. Here's his take:

Aaron Blake covers national politics and writes regularly for The Fix.

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